UC Berkeley physics professor Saul Perlmutter was a co-winner of the Nobel Prize in physics today for his work explaining how the universe is expanding. Perlmutter led Lawrence Berkeley Lab’s Supernova Cosmology Project, which made the discovery in 1998. He will receive half of the $1.4 million prize with two other scientists working in the same field getting the other half.

As described by producer Gabriela Quiros, this 2008 segment from KQED QUEST profiles Perlmutter and his team as they search for supernovae stars using a giant telescope in Hawaii. By figuring out how long ago these stars exploded, the scientists are building a history of the expansion of the universe. It was this history that led Perlmutter and another rival team in 1998 to conclude that the universe not only is expanding, it’s doing so at a faster and faster rate.